Bone generally has the ability to regenerate completely, e.g., after a fracture but requires a very small fracture space or some sort of scaffold to do so. Bone grafting is a surgical procedure that replaces missing bone to repair bone fractures that are very complex, fail to heal properly, or pose a significant health risk to the patient.
Bone grafts may be autologous (bone harvested from the patient's own body, often from the iliac crest), allograft (cadaveric bone usually obtained from a bone bank), or synthetic (often made of hydroxyapatite or other naturally occurring and biocompatible substances) with similar mechanical properties to bone. Most bone grafts are expected to be reabsorbed and replaced as the natural bone heals over a few months' time.
Bone grafts are osteogenic if they contain viable cells that are capable of bone regeneration. The current gold standard in bone graft substitutes for spine and long bone applications is autograft (i.e., using the patient's own tissue), followed by allografts. Autografts are considered osteogenic, as they contain a high number of bone forming cells. However, autographs may have limited availability and they are limited by donor site morbidity. Also, autografts may require multiple surgeries. Allografts are limited by the large variability in performance due to source and processing steps.
There is a need to produce superior bone grafts that are osteogenic and/or are able to enhance bone regeneration throughout the bone healing phase.